Remove and discard the stems and any tough ribs of the Swiss chard. Blanch the leaves in boiling water for 3 or 4 minutes, until pliable. Set aside.

To prepare the cheese filling, saute the leeks in oil for 2 minutes. Sprinkle with salt, cover and continue to cook for 5 to 10 minutes, until tender and bright green, stirring often to prevent sticking. Remove from the heat. Add the scallions, cottage cheese, basil and salt and pepper to taste and mix well.

Preheat oven to 350.

Prepare a 9 x 12-inch nonreactive baking dish with a very light coating of oil or cooking spray. Cover the bottom with the tomato slices, if using, and set aside.

Place about 1/4 cup of the filling in the center of each Swiss chard leaf. Fold the sides of each leaf toward the center, and then roll it up from the stem end to the tip to form a neat little package. Place the rolls, seam side down, in the baking dish, pour the tomato juice over them, and voer tightly with aluminum foil.

Bake for 30 to 40 minutes, until heated through.

Serve the rolls with some pan juices spooned over the top and, in desired, garnish with a dollop of nonfat sour cream or yogurt.